Core Summary: The Bioinformatics Core aims to provide statistical expertise and programming support via a transdisciplinary approach during the implementation of projects 1 to 4, as well as during TREC pilot studies. The specific aims are: 1). To provide statistical and methodological support to the Harvard TREC Center, and develop new methods of answering research questions raised by the Center;2). To interface epidemiology, basic sciences, and clinical medicine, and ensure that sound statistical methods are incorporated into all research and training activities at the TREC Center;3). To manage and maintain large data sets appropriate for use in secondary epidemiologic analyses regarding obesity and energetic issues, and for developing and refining measures of obesity and cancer-related phenotypes;and 4). To ensure timely sharing of data and their submission for centralized data collection at the Coordinating Center. Under the leadership of Dr. Bernard Rosner, Core members will meet monthly to review statistical and measurement issues across the projects. Members will participate in the annual retreat with presentations on state-of-the-art statistical methodology systems and multilevel analysis. Individual statisticians will meet regularly with the research teams they support and with the lead investigators of each developmental project. The Bioinformatics team has worked closely with all Project Leaders in developing the statistical methods and power calculations described in the proposals. The Core will actively participate in transdisciplinary research as an integral part ofthe TREC Center and will develop new methods (or apply existing methods in novel ways across projects), with a particular focus of working with pilot study recipients and new investigators.